1. Field of the Invention
This invention relates generally to a lane position method and system for a vehicle and, more particularly, to a lane position method and system for a host vehicle which uses a fusion of image data from forward-view and rear-view cameras and data from vehicle dynamics sensors to compute lane parameters, including lane curvature and the host vehicle's position and orientation relative to a lane reference path.
2. Discussion of the Related Art
Many modern vehicles include onboard cameras, which are used for a variety of purposes. One common application is a forward-viewing camera which can provide images to be used in a collision avoidance system, a lane departure warning system, a lateral control system, or a combination of these or other systems. However, conditions may arise which prevent a good image from being obtained from the forward-viewing camera. Such conditions include a leading vehicle at close range which blocks much of the camera's field of view, and low-visibility weather conditions, such as rain and fog, which obscure the camera's image. In such conditions, when a usable image from the forward-view camera is not available, systems which rely on the camera's image for input cannot be operated.
Meanwhile, many newer vehicles are also equipped with a rear-view camera, which is normally used only for backup assistance, such as providing a video image for the driver to see what is behind the vehicle. Although these rear-view cameras typically have a resolution and field of view which are more than sufficient for other image data collection purposes, until now they have not been used to supplement the images from forward-view cameras for lane position and lateral control applications.
There is an opportunity to use the image data available from a rear-view camera, and combine it with image data from a forward-view camera and other sensors, to provide a more robust lane sensing system. The resultant two-camera system not only makes use of more input data under normal conditions, but also provides a usable source of image data to allow operation of the system when conditions are unfavorable for forward-view imaging.